This page contains a dynamic collection of propagation information gathered from many different
sources. This data is extremely useful for ham radio operators and shortwave listeners to help determine whether or not long distance radio communications are possible.

Penticton Observatory SFI Measurement
WWV only updates its SFI reading once a day at 2100Z
The Penticton solar observatory takes measurements at 1700Z, 2000Z, and 2300Z
(WWV uses the 2000Z Penticton measurement)

The Penticton Observatory SFI value on 19-Apr-2012 at 2300Z
was:

139

Three Day SFI and A-index Forecast
(updated daily after 2200Z)This report issued on Apr 19, 2012 at 2200Z

Date

SFI

A-index

19 Apr

135

8

20 Apr

135

5

21 Apr

135

5

Solar Activity Forecast

Solar activity is expected to be low during days 1 - 3 (20 - 22
April) with a chance for an isolated M-class flare.

Geophysical Activity Forecast

Geomagnetic field activity is expected to be at quiet to
unsettled levels on day 1 (20 April) with a chance for brief active levels due to a recurrent solar sector boundary crossing. Quiet levels are expected during days 2- 3 (21 - 22
April).

NOAA (American) Sunspot Number
This number is reported daily around 0225Z and reports
the number of sunspots observed in the previous 24 hour period

The NOAA Sunspot number for 19-Apr-2012 was:

122

Most recent five days (oldest first):

65 77 86 78 96

GOES-15 Background X-ray Flux
This value is reported daily around 0225Z and reports the
average background x-ray flux level as measured by the GOES-15 satellite

The GOES-15 Background X-ray Flux level on 19-Apr-2012
was:

B5

Most recent five days (oldest first):

B1 B2 B2 B2 B4

Auroral Activity

Aurora (also known as "aurora borealis" or "northern lights") is caused by interaction between
the Earth's magnetic field and the solar wind (a mix of charged particles blowing away from the sun). During storms, enough of these charged particles make it through to the Earth's upper
atmosphere that they interact with the earths natural magnetic field lines. When enough of these particles collide, energy is released in the form of auroral light. In addition to
creating a pretty light show (mostly in upper latitudes), ham radio signals scatter off of these particles and can greatly enhance propagation on the VHF and UHF ham radio bands. High levels of
aurora can also make HF ham radio propagation via polar routes difficult.

This chart shows X-ray flux levels as measured by the GOES-15 satellite. The measurements
(shown in red) are used to issue alerts when X-ray flux levels exceed certain levels. Spikes on the chart correspond to solar flares. Flares are considered "significant" when flux
levels rise above the "M" level (as shown on the right side of the chart). These large flares can often wipe out the ham radio and shortwave bands almost immediately and it can take minutes
to hours for the bands to recover. If the ham radio bands seem to go dead all of a sudden, it is always a good idea to check this chart to see if a large flare has occurred
recently.

The grey line is a band around the Earth that separates the daylight from darkness. Radio
propagation along the grey line is very efficient. One major reason for this is that the D layer, which absorbs HF signals, disappears rapidly on the sunset side of the grey line, and it
has not yet built upon the sunrise side. Ham radio operators and shortwave listeners can optimize long distance communications to various areas of the world by monitoring this area as it
moves around the globe. This map shows the current position of the grey line terminator.

The following map shows Maximum Usable Frequencies (MUFs) for 3000 kilometer radio signal
paths. More importantly, the current sunspot number (SSN) and Planetary A-index are updated every 30 minutes on the bottom of this image. Additionally, the grey line position, auroral
ovals, and sun position are provided. Click on the map for more details on how to use it.

The images below are current views of the sun shown at different wavelengths of light as taken
by SOHO and the Yohkoh soft-Xray telescope. Generally, more bright regions on the disk indicates more solar activity, which usually leads to higher flux levels (which also often leads to
better ham radio and shortwave propagation). Click on any thumbnail to view a larger image.

SOHO - 17.1nm

SOHO - 19.3nm

SOHO - 21.1nm

SOHO - 30.4nm

Sometimes you may see the text "CCD Bakeout" instead of the images. This occurs when NASA
does routine maintenance and calibration on the cameras. For a more technical explanation, read NASA CCD Bakeout explanation.